The Pennsylvania Turnpike opened in 1940 and is known as the “Tunnel Highway” due to it containing seven tunnels. From east to west they were Blue Mountain, Kittatinny Mountain, Tuscarora Mountain, Sideling Hill, Rays Hill, Allegheny Mountain, and Laurel Hill. The roads and tunnels were designed as a single lane in each direction, which caused massive congestion problems by the late 1950s. This caused the Pennsylvania Turnpike Commission (PTC) to “twin” four of these tunnels by constructing a second, parallel, two-lane tunnel. This process expanded the Blue, Kittatinny, Tuscarora, and Allegheny Mountain tunnels, and closed Sideling Hill, Rays Hill, and Laurel Hill Mountain tunnels, which were bypassed.

In 2001, the PTC sold most of the property to the Southern Alleghenies Conservancy (SAC) for $1.00. The property is managed by Friends of the Pike 2 Bike, which turned the roads and tunnels into a bike trail. The bike trail is open to the public, but motor vehicles are not allowed. The buildings that housed the massive ventilation system for the tunnels are off-limits to the public.